The electronic signal transmission speed required to be processed is growing fast with the technology progress, so that the control switches or relays are required to be capable of processing signals at 1 GHz or higher frequency. The electromechanical switches or relays are for connecting or disconnecting current or circuitry with a mechanical design. The traditional contact structure of electromechanical switches is only capable of transmitting DC or extremely low frequency signals. If a processing device for high frequency signals desires to be added to the traditional contact structure with mechanical design, it will encounter problems such as large-scale cost increase and difficulties in mass production.
The MEMS switch or relay is used for resolving the problems mentioned above. In brief, it is fabricated on the silicon wafer using semiconductor technology with a potential of mass production. The micro design is capable of minimizing the volume of the switches or relays. The typical MEMS switch 5, as shown in FIGS. 1 and 2, has a pair of electrodes 11 and 14, which are separated by a thin dielectric layer 12 and an air gap or cavity 13 defined by a dielectric standoff 16. The electrode 14 is mounted on a diaphragm or a moving beam capable of mechanical displacement, and the other electrode 11 is jointed on a substrate and can not move freely. The switch 5 has two states, that is open (shown as FIG. 1) or close (shown as FIG. 2).
The MEMS switch is very small, so that the charged dielectric medium and effects of static friction always interfere with the stable actuation and release. Low insertion loss and high isolation both are acquired while the MEMS is used in the transmission of high frequency electronic signals, and will limit the gap between the electrodes 11 and 14. Therefore, the MEMS switch is restricted while being used for transmitting the high frequency electronic signals.
In addition, the MEMS is fabricated with semiconductor technology, and the processes include repeatedly oxidizing, depositing, transferring, and etching. The processes are complicated and the steps are numerous. If one of the processes is not properly performed, the entire element must be reworked, resulting in increased manufacturing time and cost.